1. Field of the Invention
The subject invention generally relates to a resin for use in a coating composition. More specifically, the subject invention relates to a resin that provides a cured film formed from the coating composition with low gloss.
2. Description of the Related Art
Coating compositions are typically applied to a substrate to provide the substrate with certain functional and aesthetic qualities, such as color, appearance, and protection. For example, coating compositions may be used to enhance appearance by providing the substrate with high or low gloss. Gloss is a measure of specular reflection and results when light reflects off a smooth substrate so that an angle of incidence is equal to an angle of reflection. Substrates with high gloss typically reflect a high proportion of specular light and are characterized by a shiny appearance. In contrast, substrates with low gloss typically reflect a low proportion of specular light and are characterized by a dull or matte appearance.
Many existing coating compositions for applications requiring low gloss are designed to include a flattening agent, such as fumed silica, in the coating composition. The flattening agent disrupts reflection of specular light. Consequently, increased levels of flattening agent provide cured films formed from the coating composition with decreased gloss. However, increased levels of flattening agent also detrimentally increase manufacturing costs of the coating composition.
Further, coating compositions including increased levels of flattening agent are prone to settling, i.e., the coating compositions are unstable. Unstable coating compositions have poor shelf life and cannot be stored for desired durations without affecting viscosity and spray-ability of the coating composition.
Additionally, at increased levels, flattening agents tend to coagulate in the coating composition. As a result, cured films formed from coating compositions including increased levels of flattening agent typically have inconsistent gloss levels over time, an unacceptable seedy appearance and do not exhibit an acceptable matte finish.
Finally, coating compositions including increased levels of flattening agent typically form cured films that are brittle and exhibit poor durability.